ETUDE DES ISOENZYMES DE LA LACTATE DESHYDROGENASE: VALEURS FREQUENTES EN FONCTION DE L'AGE CHEZ L'ENFANT, ETUDE DE LA CONSERVATION

In this study we were able to evaluate the total lactate dehydrogenase activity of serum of children year by year. We also defined by electrophoresis the normal isozyme profile for each age group. We noted that the total activity was higher during the first years of life and that during this period, the isoenzymic profile was different from that of adults: higher percentage of LDH 5 (13% as against 8% in adults) and a lower percentage of LDH 1 (19% as against 24% in adults). Furthermore, it seemed to us preferable to determine the total LDH activity on fresh serum, for a fall in activity is noted both after preservation at +4°C and -20°C. Similarly, it is preferable to trace the isoenzyme profile on the same day rather than after preservation of the samples. The average differences show clearly the disappearance of certain fractions (isoenzymes 4 and 2 after six days preservation at +4°C). However, each serum seems to behave in a somewhat unforseeable manner and the range of individual variations makes any statistical interpretation impossible.